21330940 has 24 divisors (see below), whose sum is σ = 45123120. Its totient is φ = 8469888.

The previous prime is 21330929. The next prime is 21330941. The reversal of 21330940 is 4903312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21330941) by changing a digit.

It is a nontrivial repunit in base 277.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1057 + ... + 6616.

It is an arithmetic number, because the mean of its divisors is an integer number (1880130).

Almost surely, 2^21330940 is an apocalyptic number.

21330940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21330940 is an abundant number, since it is smaller than the sum of its proper divisors (23792180).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21330940 is a wasteful number, since it uses less digits than its factorization.

21330940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7821 (or 7819 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 21330940 is about 4618.5430603167. The cubic root of 21330940 is about 277.3341378233.

The spelling of 21330940 in words is "twenty-one million, three hundred thirty thousand, nine hundred forty".